Two-way television communication unit



y 6, 1947. A. H. ROSENTHAL TWO-WAY TELEVISION COMMUNICATION UNIT Filed June 20, 1944 INVEN TOR. A001 PH H. QOSZ/VTHAL BY V fiw A T TORNE Y Patented May 6, 1947 TWO-WAY TELEVISION COMMUNICATION UNIT Adolph H. Rosenthal, New York, N. Y., assignor to Scophony Corporation of America, New York, N. Y., a corporation of Delaware Application June 20, 1944, Serial No. 541,155

7 Claims.

1 This invention relates to a unitary apparatus for picking up intelligence and translating it into electric signal impulses, as well as visibly reproducing signal impulses representative of intelligence. In particular, the invention relates to a unitary apparatus, for instance of the cabinet or box type which also can be portable, for television two-way communication which permits observation of televised intelligence ona viewing screen and simultaneously to pick '-Iup intelligence at the place of observation for transmitting it to a distant place and in particular to the one whence the observed televised intelligence comes.

More specifically, the invention is concerned with unitary apparatus for use in combination with telephone communication where a first conversant at one end of the line is enabled to view a screen on which a second conversant talking on, the other end of the line is televised, while the image of the first conversant is picked up and transmitted simultaneously to the second conversant on the other end of the line. Such an apparatus for two-way television communication can be physically combined witha sound receiver and transmitter, or r hand telephone set, which for instance, when the receiver is lifted, also switches in the television apparatus and switches it out when the receiver is replaced.

It is an object of the invention to enable the person observing the viewing screen of the apparatus to check whether the source or sources of intelligence which emit light rays within the visible, invisible or nearly visible spectral regions of light to be picked up and to be transmitted from his place, are correctly illuminated and/or positioned relative to and focused on the transmission pick-up device of his apparatus.

It is another object of the invention to enable the person observing the viewing screen of his apparatus to check whether the light emitting source or sources of intelligence to be televised from his place, are correctly illuminated and/or positioned relative to and focused on the transmission pick-up device at his place, and to bring about adjustments or changes in the setting and/or optical device for translating that intelligence upon the light-sensitive element or elements of the transmission pick-up device.

It is a further object of the invention to enable the person observing the viewing screen of his unitary transmission and visibly reproducing apparatus to check the setting and particularly the optical and/or electric conditions of operation of the transmission pick-up device of his apparatus by reproducing the electric signal impulses representative of the picked up intelligenceon the viewing screen observed by him.

It is a specific object of the invention to secure for persons communicating with one another over a telephone line and who are simultaneously and mutually televised, the natural impression that they are attentive, i. e. that one conversant is looking into the others eyes, and to this end to also enable the conversant on his viewing screen, to check on his transmission pick-up device whether he himself is properly imaged and focused thereon.

These and other objects of the invention will be more clearly understood when the specification proceeds with reference to the drawings in which Fig. 1 exemplifies rather schematically in vertical cross section and partly elevation a two-way communication apparatus according to the invention, and Fig. 2 in a similar manner a modification thereof,

It should be understood attheoutset that the invention is not limited to any particular type of apparatus for picking up intelligence and transforming it into electric signal impulses to be transmitted, or to any particular apparatus which visibly reproduces such signal impulses impressed upon it. As a transmission pick-up apparatus any electric device can be used which comprisesfor instance a light sensitive signal plate, on which the intelligence to be transmitted is beingimaged, such as an iconoscope apparatus. The electric signal impulses representative of any kind of intelligence can be visibly reproduced, for instance by means of an apparatus operating on supersonic light modulating principles, or on the principles of controlling the optical qualities of a screen, such as a screen the reflecting power, or transparency, or opacity, or refractive index of which is varied locally and temporarily by an impinging modulated cathode ray beam or stream. Apparatus which use a screen of light emitting qualities which are affected by certain radiant energies preferably cathode rays impinging upon it, such as fluorescent material type screens, canalso be used to advantage. Whatever may be the type of the apparatus used for picking up and translating the intelligence to be transmitted and fo visibly reproducing the signals representative of intelligence, the invention primarily consists in a unit in which such a pick-up transmission device and reproducing apparatus are combined for the purpose of a two-way communication and permitting the realisation of the objects of the invention set forth hereinbefore and to be gathered from the subsequent specification.

Referring to Fig. 1, it is assumed that the ele ments of the signals, particularly television signals reproducing and intelligence picking up apparatus are installed in a space enclosed in a box or cabinet I provided with a viewing opening II on its front. A suitable illuminating source l2 maybe connected with it, for instance arranged on top of cabinet I II, and emit visible light of adjustable brightness,- or not-blinding short wave or longwave invisible or nearly invisible light (ultra violet or infra-red rays, respectively) which affects, however, the correspondingly sensitized signal plate of the pick-up apparatus. The source of intelligence to be picked up and transmitted is assumed to consist in this exemplification in the face of a person iii in front of opening II who conducts a telephone conversation with another person at the other end of a telephone line. The telephone receiver and its connection with the apparatus or communication lines illustrated are not shown. It is further assumed that the conversant at the other end of the line is the object the image of which is to be visibly reproduced in the apparatus viewed by the person I8 through opening II. It should be understood, however, that instead of an image of a conversant any other information can be transmitted and/or visibly reproduced.

The viewing screen I4 of an electric signal impulses, in particular television picture signals visibly reproducing apparatus I 5, for instance of the cathode ray operated fluorescent screen type, is arranged inside cabinet III essentially in the axis t 3 from the eyes of the conversant l8 talking at this end of the line. Cathode ray tube I5 comprises a neck I6 in which the cathode ray gun, the deflecting and modulating electrodes for the cathode ray beam are arranged in conventional manner so that the signals representative of intelligence of any kind which are impressed upon the cathode ray beam in tube I5 are reproduced in and can directly be viewed on screen I4. In particular, the signals received produce on the viewing screen a picture of the conversant on the other end of the line.

Across the optical lines of vision of person I8 through opening II to screen I4, a suitable raydividing means, such as for instance a semitransparent 45 mirror I9, or prism, is arranged through which the person I8 can see the image or picture instantly produced on screen II, whereas an image of that person's face is simultaneously projected by mirror I8 through objective or imaging lens (system) upon the lightsensitive signal plate 2| of a pick-up cathode ray tube 22 of well known type, for instance the iconoscope type. The output from the signal plate 2I of transmitter tube 22 is translated through an amplifier 52 and switch 23 upon the outgoing communication line 24. The signals, in particular picture signals incoming over line 25 and to be visibly reproduced, are translated through switch 26, line 21 and amplifier II upon the cathode ray beam in tube I5.

The electrical circuits and arrangements for operating the pick-up and signals reproducing cathode ray tubes I5, 22 are well known in the art and need no detailed description or showing in the drawing. If the incoming or outgoing signals are respectively demodulated from and modulated upon carrier waves, circuits well known for these purposes can be arranged inside cabinet I0 or in an outside attachment, or in a separate unit connected with the one shown in any suitable way, such as by cable. Similarly the Sound may be transmitted and received over lines, or modulated upon carrier waves by methods and arrangements well known in the art. If the pick-up and/or signals reproducing apparatus 4 operate on the line and frame scanning principles synchronising signals for the line and frame scan in the various communicating units can be pro? duced in and transmitted from centralised equip] ments, or derived from the mains. Dealing more specifically with the communication between two conversants at the opposite end; of the communication line, the natural impres-Q sion for each of them of looking straight into thi} others eyes, can be obtained only if e. g. persor? I8 looking straight through opening II at screerii I4, gets the impression that the other conversant whose picture is reproduced on the screen looks? straight from it into the eyes of person I8. In; other words, in order to obtain the impression? of mutual, full attention, it is necessary that the, lines of sight of person I8 to the pick-up tube 22, and from the receiver tube I5 coincide. If the, reproducing and pick-up tubes would be arranged; side by side, or one above the other, the eyesofi each conversant would -be naturally focused upon} the screen of his receiver tube and not on the! pick-up tube, whereby the distant conversant to? whom the picked up image is transmitted, gets:

the impression that the imaged conversant isf looking away from him and is inattentive.

transmitted picture will By making the axis I3, along which the person: I8 looks toward the viewing screen I4 of his television reproducing apparatus, the same or es-z sentially coinciding with picture is projected and plate 2| of his pick-up at directly.

any other intelligence to be transmitted, erly focused upon signal plate 2I,

distance from that signal plate.

which can be moved over a dial distance of person or object front wall 28 of cabinet I0. there is still the danger that the distance is inaccurately estimated v occurred in the posii tron or operation of the pick-up apparatus which or that other changes have render the transmission unclear.

In order to properly focus mount 29 may be screw-threaded on the outside and engage a screw threaded support 30 so that by turning handle 3I in slit 43 in a plane about vertical to that of the drawing, mount 29 is turned within support 30 and lens 20 is raised or lowered and thereby the face of person I8 prop- I erly focused on signal plate 2| of the pick-up or transmitter tube 22.

In order to enable person l8 to check on the correct focusing, switches 23, 26 are connected through rods 32, 33 with handle 34 outside front wall 28. By pushing handle 34 toward wall 28, the communication lines 24, 25 for the outgoing and incoming signal impulses are disconnected from the tubes I5, 22 and instead the signal plate 2I is connected through amplifier 52, switch 23 (in its position shown in dotted line), line 35 and amplifier I! with the reproducing tube I5. Hence the person I8 views on screen I4 his own picture or that of the object to be televised, as it is being viewed upon transmission over communication line 24 by the distant conversant. Person I8 can thus check whether the picked up image or picture shows the desired details, or is blurred or distorted, or sharply focused.

the axis along which his; imaged upon the signal itube, his pickedup andl'i give the impression to the distant conversant that the latter is looked lens system 20, its

'After any correction has been brought about by him in his. own position relative to mirror I9, or in the position of lens system by means of handle 31, he pulls handle 34 back, or releases it, into the initial position whereby the pick-up tube 22 is connected again with the outgoing communication line 24 and the reproducing tube I5 with the incoming line 25.

It is understood that the reproducing and pickup tubes I5, 22 are operated in synchronism, and if there are more than two places or stations interconnected, synchronisation between all the pick-up and reproducing apparatus is then to be maintained by'a common synchronising signal generator. The synchronising signals may be transmitted over lines, or modulated on carrier waves transmitted along lines or by wireless the same as used for transmitting the modulating signals, the same or difierent transmission lines, and in particular different carrier wave lengths may be used for transmitting the sound. While the horizontal and vertical line scanning impulses as well as line and frame scan synchronising impulses can be translated upon tubes I5, 22 for instance from a centralized source over the communication lines 24, 25 in the position of switch 23, 26 shown in full lines. these impulses and signals can be translated upon both tubes through the branch line 44, switch 25 (both shown in dotted lines) and line 21, 35, respectively, when the transmission lines are switched off, so that the image on signal plate 2| is properly reproduced on screen l4.

Instead of using a semi-transparent mirror I9 or a prism provided with a suitably inclined reflection surface, any other suitable ray-dividing means can be used, such as for instance suitable lenses or spherical mirrors with center holes which may be fitted with other optical devices, such as lenses, prisms, etc. Illuminating light is then directed through the optical devices in the center hole upon a reflection-type screen of a cathode ray controlled light valve. and hence transmitted through a Schmidt-correction aspherical lens or spherical mirror upon the 45 mirror and the viewing screen.

In the modification of the invention shown in Fig. 2, the apparatus for'visibly reproducing signals, particularly television signals, comprises a cathode ray tube or light valve 36, for instance.

provided with a transparency controlled ionic crystal screen 31. as described in my Patent No. 2,330,171, instead of a self-luminescent screen, or direct view reflection type screen as exemplified or explained with respect to Fig. 1. ing screen 38 is arranged in the axis of sight l3 behind the suitably inclined semi-transparent mirror I 9, and a source of visible illuminating light 39 and reflector 40 are arranged on the other side of tube screen 31. The light from source 39 and refiector 40 i projected through condenser lens system 4 l transparency controlled screen 31 and projection lens system 42 upon viewing screen 38 which may consist of ground glass. Incoming signals are impressed upon the modulating electrodes in neck 43 of tube 36, for instance, in the manner described in my above patent.

Apart from this modification as to' the light valve, the details used and shown in Fig. 2 as well as the uses and advantages of this embodiment of the invention are the same as described hereinbefore with reference to Fig. 1. It should be understood, however, that by turning light valve 36 by 180, tube screen 31 can be exposed to the un- A viewobstructed direct view by the observer or conversant i8 and if properly illuminated, directly viewed by him so that screen 38 can be omitted.

It should be understood that the invention is not limited to any exempliflcation hereinbefore described or shown but is to be derived in its broadest aspects from the appended claims. Thus, for instance instead of or in addition to the adjustable arrangement of optical lens system 20, the distance of mirror I9 from signal plate 2| or tube 22 can be made adjustable; tube 22 and lens system 20 with its support 30 can also be combined in a unit adjustable relative to mirror l9, both in angular direction as well as regarding its distance therefrom. The output of tube 22 can be either translated directly or through amplifiers 52, i1 upon the reproducing tube l5, and in the latter case the amplification of the translated signals can be adjusted, if desired automatically depending upon the position of switch 23. Similarly. tube IS with tube screen [4, or tube 36 with tube screen 3! can be arranged at adjustable distance from screen 38, or lens system 42 in Fig. 2 can be adjustably arranged as to position or focal length (magnification) In the claims the term intelligence" comprises any information capable of being visibly reproduced, including, but not by way of limitation, living or inanimate objects and settings, physical phenomena, pictures, images, writings and printed matter. The term device for visibly reproducing electric signal impulses representative of intelligence includes any apparatus including a screen the self-luminescent, or light-reflecting or transmitting optical qualities of which are locally and temporarily changed by suitable radiant energy (such as cathode rays, X-rays, and radium rays) which in turn is controlled by electric signal im pulses representative of intelligence. Supersonic light modulating and image reproducing apparatus are also Within this term. The term light rays includes rays of light within the Visible, invisible and nearly visible spectral regions of light, including the visible light spectrum and the short and long wave light ray ranges near the end of that spectrum, such as ultra-violet and infra-red rays, which are capable of being visibly reproduced on a suitable viewing screen or to aifect a properly sensitized pick-up signal plate.

What I claim is:

1. A unitary two-way communication apparatus for picking up intelligence to be transmitted to a distant place and for visibly reproducing intelligence received from a distant place, essentially comprising, in combination, a pick-up and transmitting device adapted to transform light rays within the visible and invisible spectral regions and representative of intelligence to be transmitted', into electric signal impulses, means for translating said impulses upon outgoing transmitter means, a device for visibly reproducing electric signal impulses representative of intelligence, means for translating incoming signal impulses upon said reproducing device, and means for cperatively connecting said translating means either with outgoing and incoming transmitter means or with one another, so that in the latter case impulses produced in said pick-up device are visibly reproduced by said reproducing device.

2. A unitary two-way communication apparatim for picking up intelligence to be transmitted to a distant place and for visibly reproducing intelligence received from a distant place, essentially comprising, in combination, a pick-up and transmitting device adapted to transform light rays within the visible and invisible spectral regions and representative of intelligence to be transmitted into electric signal impulses, translating means including amplifying means for aid impulses upon outgoing transmitter means, a device for visibly reproducing electric signal impulses representative of intelligence, translating means including amplifying means of incoming signal impulses from incoming receiving means upon said reproducing device, and means for operatively connecting said translating means with one another so that impulses produced in said pick-up device are visibly reproduced in said reproducing device and disconnecting them at least from said incoming receiving means.

3. A unitary apparatus forpiclring up intelligence to be transmitted to a distant'place and for visibly reproducing intelligence received from a distant place, essentially comprising, =in,combina tion, a pick-up and transmitting device-adapted to transform light rays within the visible and invisible spectral regions and representative of intelligence to be transmitted, into electric-signal impulses, means for translatingmpulses upon outgoing transmitter mean'sfa idea for visibly reproducing electric signaljiimpuls'esprepresentative of intelligence meansfor'translating incoming signalimpulses uponsaid reproducing device, adiustabieoptical means in the path of said light rays for projecting and focusing them in said pick-up device; and; means for operatively connecting said pick-up device with said reproducing device so that the impulses produced in the former are visibly reproduced by the latter.

4. A unit comprising a transmission pick-up device of light rays representative of intelligence. and a device for visibly reproducing electric signal impulses representative of intelligence, essentially comprising, in combination, saidpick-up transmission device, said reproducing device and optical means for dividing light rays as exempliiied by asemi-transparent mirror, said pick-up device and reproducing device in angular relation witlrrespect to said optical-means so that light rays representativeof intelligence projected in one direction upon said optical means are transmitted onto said pick-up device and light rays emerging from said reproducing device and projected upon said optical means are transmitted in opposite direction and the optical axes of said directions essentially coincide, means for translating signal impulses produced in said pick-up device upon transmitter means, means for translating impulses representative of intelligence from receiving means upon said reproducing device, and means for operatively connecting said pick-up device and reproducing device with one another and disconnecting at least the latter from said receiving means, so that signals reproduced in said pick-up device are visibly reproduced by said reproducing device.

5. A unit comprising a transmission pick-up device of light rays representative of intelligence and a device for visibly reproducing electric signal impulses representative of intelligence, essen tially comprising, in combination, in enclosed space said pick-up transmission device, said reproducing device and optical means for dividing light rays as exemplified by a semi-transparent mirror. an observation aperture in the enclosure of said space, said pick-up device and reproducing device in angular relation with respect to said optical means and the latter arranged with respect to said aperture so that light raysrepresentative of intelligence projected in one direction through said aperture upon said optical means are transmitted onto said pick-up device and light rays emerging from said reproducing 2 device and projected upon said optical means are f:

transmitted in opposite direction through said i aperture and the optical axes of said directions essentially coincide, means for translating si al impulses produced in said pick-up devic upon 5, transmitter means, means for translating impulses representative of intelligence from receiving means upon said reproducing device, and? means for operatively connecting said pick-up device and reproducing device with one another and disconnecting at least the latter; from said receiving means, so that signals reproduced in 3 said pick-up device are visibly reproduced by said reproducing device.

6. A unit comprising a transmission pick-up device of light rays representative of intelligence 2' and a device for visibly reproducing electric signal impulses representative of intelligence, essentially comprising, in combination, said pick-up transmission device, said reproducing device and optical means for dividing light rays as exemplified by a semi-transparent mirror, said pick-up device and reproducing device in angular relation with respect to said optical means so thatlight rays representative of intelligence projected in one direction upon said optical means are transmitted onto said pick-up device and light rays impulses produced in said pick-up device upon transmitter means, means for translating impulses representative of intelligence from receiving means upon said reproducing device, and

means foroperativelyconnecting said pick-up device and reproducing device with one another and disconnecting at least the latter from said receiving means, so that signals reproduced in said pick-up device. are visibly reproduced by said reproducing device.

7. A unitary apparatus for television transmission and reception, essentially comprising, in combination,;.; a',television pick-up and picture signal transmitting'devlce, means for translating said signals upon outgoing transmitter means, a device for visibly reproducing picture signals, means for translating incoming picture signals from receiving means upon said reproducing device, adjustable optical means for projecting and focusing-an image to be televised onto said pickup device, and means for operatively connecting said pick-up device with said reproducing device and disconnecting the latter from said receiving means, so that picture signals produced in said pick-up device are visibly reproduced by said reproducing device.

ADOLPH H. ROSENTHAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,932,253 Ives l Oct. 24, 1933 1,980,150 Baird Nov. 6, 1934 2,308,381 Mertz. Jan. 12, 1943 2,315,784 Goodale Apr. 6, 1943 

